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• To realize the relative validity of one's convictions, and yet stand for them unflinchingly is what distinguishes a civilized man from a barbarian.

• Cassel is 10 per cent Walras and 90 per cent water.

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• Gentlemen, a depression is for capitalism like a good, cold douche. (To economics students, recorded by RL Heilbroner, The Embarrassment of Economics, 1996)
• Innovation is the market introduction of a technical or organisational novelty, not just its invention. (Theorie der wirtschaftlichen Entwicklung, 1911)